Fluidic oscillators as shown in FIG. 1 are well known and particularly useful in liquid spray applications such as washer nozzles. Such fluidic oscillators are typically manufactured of molded plastic and comprise a fluidic oscillator circuit OC or silhouette molded in a chip or insert 13 and a housing 10 having a cavity 11 into which the chip or insert 13 is forcibly inserted. A source of fluid under pressure is supplied to the power nozzle PN in the fluidic oscillator circuit OC by way of an inlet pipe or barb 12. Care is taken in the design to assure a seal between the housing internal surfaces and the mating surfaces of the chip or insert. In mass manufacturing of such chips and housing, small loose plastic particles can be carried by liquid flow and can clog portions of the fluidic circuit or outlet thereby blocking the flow of liquid (washer liquid in the case of a washer nozzle). In the case of fluidic oscillators, this interrupts the oscillation function.
There have been efforts to place screens or discrete filter screens upstream of the fluidic circuit, but these expedients add cost and complexity to the device. Thus, the problem solved and addressed by the present invention is potential clogging of liquid flow devices. The invention solves this problem by integrally providing extra places or enlargements and spaced posts for contaminants or loose particles to lodge or become trapped in areas other than main flow areas so that there are additional flow passages or ways for liquid to flow if a contaminant or particle blocks one or more passages or spaces between posts.
The invention provides for low profiles in areas specifically designed to encourage contaminants to flow into and stop in areas other than the power nozzle or the main jet flow area. By providing integral molded enlargements with spaced posts in areas as described above, the fluidic nozzle can continue to function in spite of partial upstream blockage in the enlargement area because a power jet channel is still completely open. In the absence of the present invention, contaminants usually flow directly into the power nozzle or the main jet area, thereby making the system nonfunctional.
The invention features a molded fluidic device having a power nozzle with a width W and a coupling passage coupling a source of fluid to said power nozzle. The coupling passage has an enlargement and a plurality of posts spaced across the enlargement, the spacing S between each post being less than the width of the power nozzle with the sum of spacings S being greater than the width W and the coupling passage and posts being integrally molded with the fluidic device. The dimensions of the coupling passage, the planar enlargement and the spacing S are such that the fluidic flow rate from the source to the power nozzle is substantially unaffected when a foreign particle blocks any one of the spaces between the posts. In a preferred embodiment, fluidic is a liquid oscillator which issues a fan spray of liquid droplets to ambient and wherein the dimensions of the planar enlargement and the spaces S are such that the fan spray is substantially unaffected when one or more foreign particles is trapped in any one or more of the spaces. The coupling passage and the posts are molded as an integral molding with the fluid device. A housing member into which the integral molding is inserted has a coupling to a source of liquid under pressure.
The invention has advantageous usage in molded liquid-spray nozzles, particularly when the liquid is sprayed to ambient; and still more particularly when the liquid is a wash liquid to be sprayed on a surface to be washed, such as vehicle glass.
Benefits of the present invention include the following:
1. Provides for prolonged life for the system in which the nozzle is used. PA1 2. Provides a filter mechanism free of cost compared to in-line filters which require a separate component and some of which require a hose to be cut to include the filter, install the filter, etc.